TWI637162B - Radial polarized light surface plasma excitation device - Google Patents

Abstract

A surface-plasma excitation device for radial polarization, which solves the problem that a lens for focusing in front of a metal film to be tested is usually required to have a large incident angle, and is usually a high numerical aperture immersion microscope objective, thereby causing The problem of expensive construction is that the surface plasma excitation device replaces the microscope objective with a reflector, and the reflector is reflected by the quadric surface after the beam is incident, and the beam can be incident on the metal to be tested at a large incident angle. The film thereby generates surface plasma excitation, thereby constituting the present invention.

Description

Radial polarized light surface plasma excitation device

The present invention relates to an optical device, and more particularly to a surface-plasma excitation device for radial polarization.

As shown in FIG. 7, a surface-plasma excitation device for conventional radial polarization, a laser beam 911 is emitted from a laser generator 91, and the laser beam 911 is generated by a radial polarization converter 92. The effect of the radial polarization is that the polarized beam 911 after the polarized light is reflected by the objective lens 93 on the surface of the metal film 94 to generate a surface plasma resonance phenomenon. After the reflected laser beam 911 returns to the objective lens 93, the image is sensed. There is an image on the detector 95 to show the phenomenon of sudden drop in light intensity at the surface of the plasma resonance, which is commonly used in the field of biomedical research. In order to achieve the desired accuracy of the detection result, the objective lens 93 that the laser beam 911 passes before being reflected on the surface of the metal film 94 has good precision and stability requirements, especially high numerical aperture requirements (in order to achieve high Numerical apertures, usually using immersion microscope objectives, are therefore costly.

As shown in Fig. 8, the objective lens 93 is replaced by a lens group 96 composed of a lenticular lens 961, 962, based on the conventional surface plasma excitation device described above, and the parallel beam is enlarged by double focusing. The incident angle is focused on the metal film 94, whereby the function of the objective lens 93 described above is achieved at a lower price. However, the angle at which the light is refracted by the convex lenses 961, 962 of the lens group 96 corresponds to the object of the larger refractive index range, which is limited by the focusing effect of the convex lenses 961 and 962 themselves. It is not possible to provide a sufficiently large surface plasma excited incident angle condition, thus limiting the feasibility and use of the entire surface plasma excitation device.

Therefore, how to solve the problem of the foregoing surface plasma excitation device is the focus of the present invention.

The main object of the present invention is to solve the above problems and provide a surface-plasma excitation device for radial polarization, mainly for the same specification, the reflector can provide a light beam incident on the metal film to be tested at a large incident angle. Therefore, when a large incident angle is required, the problem that the lens group is limited by the incident angle provided by the surface plasma excitation device can be solved by the reflector.

In order to achieve the foregoing objective, the present invention provides a surface-plasma excitation device for radial polarization, comprising: a surface-plasma excitation device for radial polarization, comprising: a light source, which is Converting the light source into one of the radially polarized light beams, and then penetrating a beam splitter according to the path along which the light beam continues to travel, and providing a reflector on the path of the beam passing through the beam splitter portion, and the beam splitting the beam at the beam splitting An image sensor is disposed in a direction in which the mirror portion is reflected; wherein the reflector is concave to form a quadratic surface and an opening facing the direction in which the light beam travels, and the metal film to be tested is at the opening of the reflector The central position is disposed on a side of a glass substrate facing the beam splitter, the light beam entering the reflector in parallel, reflecting in the direction of the glass substrate in the quadric surface, and focusing on the metal at the same incident angle The film forms a focus point, and any of the light beams has the same angle with respect to the incident angle and the reflection angle of the normal point of the metal film with reference to the focus point, and the incident angle provides a sufficiently large angle Forming the total reflection phenomenon of the surface plasmon excited on the metal film surface.

Wherein, the reflector is filled with a transparent material in the space formed by the recess, and the refractive material has a refractive index of between 1.3 and 1.8.

Wherein, the transparent material body is a transparent optical glue, and the refractive index is preferably 1.51.

Wherein, the quadratic surface is a paraboloid.

Another surface-plasma excitation device for radial polarization, comprising: a light source, wherein the light source is converted into a beam of radially polarized light by a radial polarization generating unit, and then penetrates through a path in which the beam continues to travel. a beam splitter, and a transparent material body is disposed on the path of the beam passing through the beam splitter portion, the transparent material body has a convex and quadratic surface and a plane, and a reflective coating is formed on the surface An image sensor is disposed in a direction in which the beam is partially reflected by the beam splitter; wherein the reflective coating forms a concave quadratic surface along the surface, and the plane faces the direction in which the beam travels, and the metal film to be tested is The central position of the plane is disposed on the plane and faces the beam splitter. The beam enters the transparent material body in parallel and is reflected in the direction of the metal film in the concave quadratic surface of the reflective coating, and is focused at the same incident angle. In the metal film to form a focus point, the incident angle and the reflection angle of any of the light beams with reference to the aforementioned focal point perpendicular to the normal line of the metal film have the same angle, and the incident angle provides a sufficiently large angle Forming an angular range of total internal reflection of the excitation of surface plasmon at the metal film surface.

Wherein the light source is a collimated light source emitted by a light source generator, and the light source forms the light beam through a spatial light filter and the radial polarization generating unit; the radially polarized light generating unit includes a radial polarization The converter, according to the path of the beam, the radial polarization converter is disposed in front of the beam splitter, and the radial polarization converter can be disposed before or after the spatial light filter.

Wherein, the light source generator is a laser generator, and the light beam is a collimated laser beam; or the light source generator comprises a white light source and a color filter, and the white light source emits light and penetrates the light source a color filter to form the light beam; or the light source generator is a white light source to form the light beam.

The above and other objects and advantages of the present invention will be readily understood from

Of course, the invention may be varied on certain components, or in the arrangement of the components, but the selected embodiments are described in detail in the specification and their construction is shown in the drawings.

(customized part)

91‧‧‧Laser Generator

911‧‧‧Laser beam

92‧‧‧radial polarization converter

93‧‧‧ objective lens

94‧‧‧Metal film

95‧‧‧ sensor

96‧‧‧ lens group

961‧‧‧ convex lens

962‧‧‧ convex lens

(part of the invention)

1‧‧‧Light source generator

11‧‧‧ Beam

2‧‧‧radial polarization converter

3‧‧‧Spatial optical filter

5‧‧‧beam splitter

6‧‧‧Reflector

61‧‧‧ quadric surface

62‧‧‧ openings

63‧‧‧Transparent material body

64‧‧‧ space

65‧‧‧Hemisphere

7‧‧‧Image sensor

8‧‧‧Metal film

81‧‧‧ glass substrate

11’‧‧‧ Beam

111’‧‧‧ Beam

112’‧‧‧ Beam

L1‧‧‧ normal

L2‧‧‧ normal

θ 1‧‧‧ incident angle

θ 2‧‧‧reflection angle

θ 3‧‧‧ incident angle

θ 4‧‧‧ reflection angle

6A‧‧·reflective coating

61A‧‧‧ quadric surface

63A‧‧‧Transparent material body

631A‧‧‧ surface

632A‧‧ plane

Fig. 1 is a schematic view showing the configuration of a surface plasma excitation device according to a first embodiment of the present invention, in which a transparent material body is used as a medium.

Fig. 2 is a partially enlarged schematic view showing the state of reflection of the light beam at the reflector in Fig. 1.

Fig. 3 is a schematic view showing the configuration of a surface plasma excitation device according to a second embodiment of the present invention, which is free from a transparent material body and is only a space.

Figure 4 is an image of the surface plasma resonance obtained by the image measuring device in the actual operation of the present invention.

Fig. 5 is a schematic view showing the arrangement of a surface plasma excitation device according to a third embodiment of the present invention, in which a transparent material body is used as a medium, and a reflective coating film is formed on the surface of the transparent material body.

Figure 6 is a partial enlarged view of the fifth figure at the circle of the reflector.

Figure 7 is a schematic view of a surface plasma excitation device, which is disposed in front of a metal film as an objective lens.

Fig. 8 is a schematic view showing another conventional surface plasma excitation device, which is disposed in front of the metal film as a lens group.

Referring to Figures 1 through 6, the structure of the embodiment selected for use in the present invention is for illustrative purposes only and is not limited by such structure in the patent application.

This embodiment provides a surface-plasma excitation device for radial polarization, and a preferred embodiment, as shown in FIG. 1, includes a light source generator 1, a radial polarization converter 2, and a spatial light filter. 3, a beam splitter 5, a reflector 6 and an image sensor 7, the radial polarization converter 2, belonging to a radial polarization generating unit.

As shown in Fig. 1, the light source generator 1 emits a light source 11, which is collimated, and the light source 11 is split into a light beam 11' via the spatial light filter 3 and the radial polarization generating unit. In the present embodiment, the radial polarization converter 2 belonging to the radial polarization generating unit is behind the spatial light filter 3, and the radial polarization converter 2 is disposed in front of the beam splitter 5, so that the beam 11' is generated. Thereafter, the radial polarization converter 2 and the beam splitter 5 are sequentially penetrated according to the path in which the beam 11' continues to travel, and the reflector 6 is disposed in a path through which the beam 11' is partially penetrated by the beam splitter 5, and the beam 11' The image sensor 7 is provided in a path partially reflected by the beam splitter 5.

Referring to FIG. 2 again, the reflector 6 is concave, so that a quadratic surface 61 and an opening 62 are formed in the reflector 6, and the quadric surface 61 described herein is a paraboloid in the embodiment, and the opening 62 In the direction in which the light beam 11' travels, the metal film 8 to be tested is disposed at one side of the opening 62 of the reflector 6 on one side of the glass substrate 81 to face the beam splitter 5. The light beam 11' enters the reflector 6 in parallel, is reflected in the direction of the glass substrate 81 in the second curved surface 61, and is focused on the metal film 8 at the same incident angle to form a focus point and then reflected, either light beam 11' The incident angle θ 1 and the reflection angle θ 2 of the normal line L1 of the focal point perpendicular metal film 8 have the same angle, and the incident angle θ 3 of the normal line L2 and the reflection angle θ 4 also have the same angle, and The incident angle θ 1 provides a sufficiently large angular range to form a surface-plasma-excited total reflection phenomenon on the surface of the metal film 8.

In the present embodiment, the light source generator 1 is a laser generator, and the aforementioned beam 11' emits a collimated laser beam.

In the present embodiment, the reflector 6 is filled with a transparent material body 63 in the space formed by the recess. The refractive index of the transparent material body 63 is between 1.3 and 1.8, and the refractive index of the transparent material body 63 is The rate is best at 1.51. This transparent material body 63 is, for example, an optical glue. In addition, as shown in FIG. 3, in the second embodiment of the present invention, there is no transparent material body 63 in the reflector 6, that is, a space 64 formed by only the concave portion of the reflector 6 at this time. Approximately 1, a half ball 65 is placed in front of the substrate of the metal film.

In the foregoing embodiment, the surface-plasma excitation device of the radial polarization is emitted by the light source generator 1, and the light source 11 passes through the radial polarization converter 2 and then passes through the space. The optical filter 3 is expanded to form a collimated beam 11'. The beam 11' then passes through the beam splitter 5, and is split by the beam splitter 5 into a two-part penetrating beam 111' and a two-part reflecting beam 112'. The two-part penetrating light beam 111' is focused on the surface of the metal film 8 via the reflector 6 and the transparent material body 63, and the surface-plasma-excited total reflection phenomenon is formed on the surface of the metal film 8 as described above, and is reflected back. The beam splitter 5 reflects the image on the image sensor 7 again. As shown in FIG. 4, in the actual operation of the surface plasma excitation device of the present invention, an image of the surface plasma resonance obtained by the image sensor is used to demonstrate the surface plasma excitation of the radial polarization of the present invention. The device is implemented as such.

When the light beam 111' enters the reflector 6, it is incident on the metal film 8 by the secondary curved surface 61 in a reflective manner, because the lens group changes the light beam in a refractive manner as compared with the conventional lens group. The traveling direction allows the light beam 111' to be incident on the metal film 8. For the same specification, as in the case where the light beam 111' penetrating the beam splitter 5 has the same width, the reflector is opposed to the conventional lens group. It is possible to provide a light beam incident on the metal film 8 at a large incident angle. Therefore, it is not difficult to find out from the above description that the advantage of the present invention is that if a large incident angle is required, but it is not desired to be limited by the angle limitation of the surface plasma excitation device, the surface electric can be solved by installing a reflector. The problem of the angle of incidence of the slurry excitation device.

Of course, there are many examples of the invention, with only minor variations in the details. In the first and second embodiments, the radial polarization converter 2 of the radial polarization generating unit is disposed behind the spatial optical filter 3, but the radial polarization converter 2 may also be disposed in the spatial optical filter 3. Before (not shown), after the light source generated by the light source generator 1 passes through the radial polarization converter 2, the light beam 11' is generated by the spatial light filter 3, and the same as the foregoing embodiment can be achieved. efficacy. Furthermore, the light source generator may also be composed of a white light source and a color filter (not shown), and the white light source emits light and penetrates the color filter to form the light beam 11' of the light source 11 as in the foregoing embodiment. Or, the light source generator may be a white light source to form the light beam 11', and the same effect as the foregoing embodiment can be achieved.

Further, as shown in the fifth to sixth embodiments, the third embodiment of the present invention differs from the foregoing embodiments in that the reflective coating 6A having the same function as the reflector 6 of the foregoing embodiment is used in the embodiment. A transparent material body 63A is formed in a path through which the beam 11' is partially penetrated by the beam splitter 5 (for example, formed by using the mask 6 as a mold), and the transparent material body 63A has a convex and quadric surface 631A and a plane. 632A, a reflective coating 6A is formed on the surface 631A, and in this embodiment, the reflective coating 6A is formed on the surface 631A by coating.

The reflective coating film 6A of the third embodiment forms a concave secondary surface 61A with the surface 631A, and the plane 632A faces the direction in which the light beam 11' travels. The metal film 8 to be tested is disposed at the center of the plane 632A at the plane 632A. And facing the beam splitter 5, the light beam 11' enters the transparent material body 63A in parallel and is reflected in the direction of the metal film 8 in the concave secondary surface 61A of the reflective coating film 6A, and is focused on the metal film 8 at the same incident angle. A total reflection phenomenon in which surface plasma excitation is formed on the surface of the metal film 8 as in the foregoing embodiment is achieved.

The above description of the embodiments is intended to be illustrative of the invention and is not intended to limit the scope of the invention.

From the above detailed description, it will be apparent to those skilled in the art that the present invention can achieve the foregoing objects and is in accordance with the provisions of the Patent Law.

Claims (10)

A surface-plasma excitation device for radial polarization, comprising: a collimated light source, wherein the collimated light source is converted into a beam of radially polarized light by a radial polarization generating unit, according to the path of the beam continuing to travel The sequence further penetrates a beam splitter, and a reflector is disposed on the path of the beam passing through the beam splitter, and an image sensor is disposed in a direction in which the beam is partially reflected by the beam splitter; wherein the reflector is Forming a quadratic surface and an opening facing the direction in which the light beam travels, the metal film to be tested is disposed at a center of the opening of the reflector on a side of the glass substrate facing the beam splitter, The light beam enters the reflector in parallel, is reflected toward the glass substrate in the quadratic surface, and is focused on the metal film at the same incident angle to form a focus point, and any beam is perpendicular to the metal with reference to the focus point. The normal angle of incidence of the film and the angle of reflection have the same angle, and the angle of incidence provides a sufficiently large angular extent to form a surface-plasma-excited total reflection phenomenon on the surface of the metal film. A surface-plasma plasma excitation device according to claim 1, wherein the reflector is filled with a transparent material in a space formed by the recess, and the refractive index of the transparent material body is between Between 1.3 and 1.8. The surface-plasma plasma excitation device according to claim 2, wherein the transparent material body is a transparent optical adhesive, and the refractive index is preferably 1.51. A surface-plasma excitation device according to claim 1, wherein the quadric surface is a paraboloid. A surface-plasma excitation device for radial polarization, comprising: a collimated light source, wherein the collimated light source is converted into a beam of radially polarized light by a radial polarization generating unit, according to the path of the beam continuing to travel Passing through a beam splitter, and providing a transparent material body in a path through which the beam penetrates the beam splitter, the transparent material body has a convex and quadratic surface and a plane, and a reflective coating is formed on the surface. And an image sensor is disposed in a direction in which the light beam is partially reflected by the beam splitter; wherein the reflective coating forms a concave quadric surface along the surface, and the plane faces the direction in which the light beam travels, to be tested The metal film is disposed on the plane at a central position of the plane facing the beam splitter, and the light beam enters the transparent material body in parallel and is reflected in the direction of the metal film in the concave quadratic surface of the reflective coating film, and is the same The incident angle is focused on the metal film to form a focus point, and the incident angle and the reflection angle of any one of the light beams with reference to the normal point of the metal film perpendicular to the focus point have the same angle, and the incident angle provides Large enough angular range may be formed of total reflection phenomenon surface plasmon excited on the metal film surface. A surface-plasma plasma excitation device according to claim 5, wherein the transparent material body has a refractive index between 1.3 and 1.8. A surface-plasma plasma excitation device according to claim 6, wherein the transparent material body is a transparent optical adhesive, and the refractive index is preferably 1.51. A surface-plasma excitation device according to claim 5, wherein the quadric surface is a paraboloid. The surface-plasma excitation device of any one of claims 1 to 8, wherein the collimated light source is emitted by a light source generator, and the collimated light source passes through a spatial light filter and the Radially polarized light generating unit to form the light beam; the radially polarized light generating unit includes a radial polarization converter, the radial polarization converter is disposed in front of the beam splitter according to a path of the light beam, and the radial polarization The converter can be placed before or after the spatial optical filter. A surface-plasma plasma excitation device according to claim 9, wherein the light source generator is a laser generator that emits a collimated laser beam; or the light source generator has a white light The light source and a color filter are formed by the white light source to emit light and penetrate the color filter to form the light beam; or the light source generator is a white light source to form the light beam.